An interchangeable lens in which a tilt of an optical axis of a shooting optical system and a projection lens system can be easily adjusted. An interchangeable lens comprising a lens barrel portion holding a lens group; a lens mount detachably coupled to a camera main body; and a spacer sandwiched between the lens barrel portion and the lens mount. The spacer has, in a circumferential direction of the interchangeable lens, first seat surfaces protruding in the optical axis direction at one surface thereof, and has, in the circumferential direction, second seat surfaces protruding in the optical axis direction at the other surface thereof. One seat surfaces of the first seat surfaces and the second seat surfaces are disposed with different heights such that a surface defined by the second seat surfaces has an angle with respect to a surface defined by the first seat surfaces.